The importance of state full VNF’s

What’s a VNF you ask? A VNF is a Virtualized Network Function and these things will be a key building block as networks adopt cloud technology. Many hardware vendors (Routers, Policers, Firewalls, etc) are extracting the software from their devices and deploying it on Virtual machines. In order for the clouds that host these new virtual machines to provide resiliency however, the vendors must separate the VM state information from the executing software.

Many of the cloud based infrastructures are based on OpenStack which includes a separate block storage component (cinder) for VM state information. With state information safely stored separately, VM’s can go off line and be instantly replaced by a new VM that is spun up on other resources in the cloud. The new VM gets its state information from cinder and the resource is back online in the blink of an eye, doing exactly what it was doing previously.

If vendors do not separate the state information in their VNF’s then the VM comes back on line but has no idea what it was previously doing. VNF vendors that are targeting highly available environments like service providers, will need to address the need for the separate storage of state.

I recently attended a conference on Carrier Network Virtualization in Paulo Alto California and was able to take to vendors about their VNF implementations. Vendors with existing products are busy making the shift from dedicated hardware to VNF’s and will address the separation of state at a later date. Vendors implementing new VNF’s are in a better position to design in this aspect right from the start.